Berkshire also reports a 4 percent increase in its Wells Fargo stake. While it's a smaller hike by percentage, the holdings are so big to start with that the new shares are worth over $609 million at today's close of $35.21.

The entire stake of 439.8 million shares is worth almost $15.5 billion, making it Berkshire's new top holding by market value. It tops Coca-Cola, the long-time number one, with a market value of $14.7 billion.

Berkshire has been consistently adding to its Wells Fargo stake while its Coca-Cola holdings have remain unchanged. Another factor: Wells shares are up 6.7 percent over the past three months, while Coke has dropped 2.9 percent.